Dissolved oxygen (DO of Dissolved Oxygen) is gaseous oxygen (O2) which is dissolved in water. Natural chemical processes dissolve gases such as oxygen, nitrogen and carbon dioxide in water until saturation is reached. How much oxygen can be absorbed depends on many factors, such as temperature, salinity and pressure. In general, colder water can bind more oxygen than warmer water.

Most oxygen is taken up by water from the atmosphere, with turbulent flowing water, wind and waves aiding oxygen uptake from the air. Since oxygen is also produced during photosynthesis by plants and algae, the turbidity of the water, for example, also has an effect on the oxygen content, since it weakens the light that hits the algae and aquatic plants.

The greatest consumption of oxygen in water occurs through the respiration of animals, microbes and plants, but also through the decomposition of dead organic matter by microbes and fungi. Furthermore, the dissolved oxygen can decrease when the water body warms up

The DO850/8500 series instruments from Apera Instruments provide stable and accurate DO values in the shortest possible time using an optical electrode. Due to the handy as well as dust- and waterproof (IP57) design, the meters are suitable for use in almost all environments.

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